Human and drug smuggling, if you’re into that sort of thing.
Hey, I can meet some of my future patients there! 
While there are many great places an hour or so away, for some nice day hiking check out Sabino Canyon. It’s right there in Tuscon.
Seconding Sabino Canyon for day hikes both early & late. It’s a bit too gentrified / geriatric-afied for hard core hikers, but if you just want a pleasant couple hours in the Great Outdoors(r)™ it’s nice.
The folks above mentioned the Pima air museum & the DoD “Boneyard” aircraft storage facility. If you’re into that stuff at all it’s worth a visit.
Here’s a bit more detail / background … It’s formally the 309th AMARG http://www.dm.af.mil/units/amarc.asp. These folks http://www.pimaair.org/ are a darn good civilian air museum just outside the air base fence that also offers tours of the boneyard itself. From their home page click the AMARG tab for details.
Wife went to UofA and reminds me that the Fine Arts department has quite a museum.
Yah, but in July it’s likely to be 105 and high humidity. Not great hiking weather. On the other hand, if the monsoon gods have been good, there may be a running creek in the canyon which is a great way to cool down.
Every time I see this thread I think ‘melt.’
Sorry, Just had to get that out of my brain.
Tucson’s cooler than Phoenix, shockingly. It also gets a lot more rain, so depending on when the monsoons hit it may well be pretty pleasant when it’s not raining.